1. Field of the Invention
This invention pertains to over-the-road semitrailer trucks and in particular to a tandem arrangement of trucks wherein a lead truck pulls a second, tandem-connected truck which is supported by a dolly connected to the pulling truck with drawbar. This disclosure deals with a new and improved drawbar for securely interconnecting the two trailers.
2. Description of the Prior Art
Because of varying state regulations regarding spacing between axles of tandem trailers, it is necessary to provide a drawbar interconnecting the two trailers that has the capability of being adjusted to different lengths. Telescoping members are easily adjusted, however, as with any telescoping members there can be excessive vertical deflection as well as lateral swaying during transit and which must be limited to properly control movement of the second trailer and to prevent permature failure and wear of the telescoping drawbar. While telescoping drawbars have been disclosed in the art such as that shown in U.S. Pat. No. 3,717,363 (1973) to H. Berends, problems can occur when such a complicated mechanism is provided. Further, the patent referred to, while providing internal stops which limit extension of the telescoping tubes, the internal stops do not provide automatic alignment of locking openings and do not provide a feature of securely fitting together telescoping members.